


Positive Reinforcement

by Quercusrobur



Category: Doctor Who, Doctor Who & Related Fandoms
Genre: Christmas Fluff, Fluff and Smut, Handcuffs, Multi, PWP, no angst i swear
Language: English
Status: Completed
Published: 2018-12-15
Updated: 2018-12-15
Packaged: 2019-09-19 16:21:30
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,767
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17005023
Author URL: https://archiveofourown.org/users/Quercusrobur/pseuds/Quercusrobur
Summary: “You taste of eggnog,” he says, as if imparting an important secret. Jack can feel a grin spreading across his face; he couldn’t stop it if he tried. Surreal it may be, but the opportunity is far too good to waste.“Come and get it,” he suggests, and takes another sip.





	Positive Reinforcement

**Author's Note:**

> _Holiday fluffy fluffy fluff, turned smutty. Eggnog: delicious or mind-altering? Discuss._

“What did you call this?” The Doctor is perched askew at the bar, one knee threatening passers-by, the other entirely in Jack’s personal space - which isn’t at all a problem, really.

“Eggnog. You’ve never had it before?”

He’d just _found_ him here, which was bizarre enough; the Doctor’s rather tipsy happiness sent the day right into surreal. Sat here chattering away to no one in particular about the theoretical difficulties of hyperspace, clearly being watched over by the bartender who was subtly encouraging other people in other directions and replying to the Doctor just enough to keep him from wandering off. Jack ignored the hints to go elsewhere, of course.

Holding up an index finger dramatically, the Doctor declares, “I like it!”

“Of all the things… You’re drunk, I think,” Jack says, amused. “Or… I didn’t think alcohol did much for you?” He reaches over and snags the Doctor’s glass, sniffs it quizzically, and takes a sip. “Yech. There’s no alcohol in here, Doctor -” but the Doctor’s eyes light with a predatory gleam and before Jack can react he leans forward and licks the trace of eggnog from Jack’s lip.

“You taste of eggnog,” he says, as if imparting an important secret. Jack can feel a grin spreading across his face; he couldn’t stop it if he tried. Surreal it may be, but the opportunity is far too good to waste.

“Come and get it,” he suggests, and takes another sip.

\-----

“In here,” River says, attempting to brush snow from her hair. The unforeseen consequences of introducing the Doctor to eggnog had put paid to her plans for a night out. “I know the… bartender…” Her brain hiccups to a stop. A night in, on the other hand...

“I can't believe you just _left_ him,” Amy says, starting to unwind her scarf. “I mean, have you met the man? He could find trouble on a Sunday evening in… _Sheffield_ , probably.”

“Antarctica,” suggests Rory.

“On second thought,” River interjects hurriedly, “I can handle this myself, why don't you two go have a nice night out by yourselves?” Preferably before noticing the spectacle at the bar.

“We can help you first -”

“No, no, you go on. Sorry to interrupt your shopping.” Parents disposed of, she sheds her coat and makes her way to the bar, taking the seat next to Jack and cocking an eyebrow at the bartender.

“Sorry, Dr Song,” she says quietly. “Your fellow seemed to know him, and next time I looked over, well…” She shrugs.

“Quite alright,” River assures her. “It tends to happen. Thank you for watching him.” Jack jumps when he hears her voice and she grins. “Excuse me. We'll be out of your way shortly.” With a wink, the bartender sets a closed plastic bottle of eggnog on the bar and turns away. Leaning in close to Jack's ear, River breathes, “Forgetting something?”

“Never,” Jack says, pulling away from the Doctor just enough to speak. “Hello, River.”

\-----

Suddenly the situation makes more sense; although why she left the Doctor here alone Jack can’t guess. “Jack, what are you doing?” the Doctor whines, robbed of his eggnog-flavored target. His face lights up as he notices River. “River! You're back. Did you know that eggnog is absolutely delicious? And look what I found! Or maybe he found me.” He sounds so delighted Jack can’t help kissing him again.

“You are forgetting something.” Jack can hear her smile as she comes around beside him. Sliding fingers through the back of the Doctor’s hair, she pushes at him lightly. “My turn, sweetie.”

“Do you taste of eggnog too?” the Doctor asks. He has one long leg thrown over Jack’s, boot hooked around his shin, and it tenses to keep him upright as he leans toward her.

River grins. “Not yet,” she says, and bends down to kiss Jack. He has no hands free for her - the one nearer her is down the back of the Doctor’s trousers and he’s not quite sure when that happened - but he has missed those laughing eyes and he opens his mouth eagerly as she licks at his lips experimentally.

“Oi! That’s my…” Apparently unable to decide which of them to complain to, the Doctor subsides.

“You don’t taste of eggnog,” River points out, after a minute or a few.

“Well I have to keep - hey!” Jack reaches for the glass but the Doctor has stolen it.

He widens his eyes innocently as Jack takes the glass back. “You looked busy.”

“Alright, boys, I think it’s time we headed home.” She has that lovely smirk on now; Jack quickly drains the last of the eggnog, the better to lure the Doctor along.

-+-+-+-

They tumble in through the doorway, laughing breathlessly, the Doctor tangled in Jack’s arms, and River slams the doors after them to keep the snow out. “Cold as the deep dark out there, I don’t know how you don’t feel it,” River complains, hanging her coat on the coat rack.

“I do,” Jack says, “it’s him who -” but the Doctor kisses him again and hell, it’s really not important; leaning against the console, Jack pulls the Doctor flush against him and just enjoys the feel of him, solid and real in Jack’s arms, where he always should be but so rarely is. He tastes of cinnamon and nutmeg and his hair is snow-spangled and tousled; he has burrowed into Jack’s coat, one hand tugging at the back of his braces, the other tucked into his back pocket. There's a snowflake melting in his eyelashes. He pulls away, eyes Jack appraisingly.

“I should like some more. Where did you put it?”

“What?”

“Here,” River calls, dangling a plastic bottle from her fingertips enticingly. Disentangling himself hurriedly, the Doctor steps toward her, but instead of offering him the eggnog River takes a sip and smirks at him.

Unfazed, he says, “I suppose you’re feeling left out,” hooks a hand around the back of her neck, and pulls her to him. Jack takes the opportunity to shed his coat and grabs the bottle River is holding out to him behind the Doctor’s back.

“But I meant -” the Doctor says, before Jack catches him up into another eggnog-flavored kiss. He is willing enough but starting to get impatient; the biting is rather a giveaway. “- I wanted -” River claims him again. “- to drink it!” Jack laughs, tugs the Doctor's coat off, and hands River the eggnog back as he spins the Time Lord away. “Jack!”

“Live a little, Doctor. I haven't seen you in ages.” He smiles down at his sometime-lover; the Doctor's lips quirk up and he brushes a thumb across Jack's cheek before pulling him into a brief, tender kiss.

“I missed you too. But I still want the eggnog.”

Jack would be perfectly content to give it to him and move on to more interesting activities, but River is waiting and once something turns into a competition between those two he has very little say in it. “I don't have it,” he whispers, and licks the Doctor's ear. “But I know who does.”

“River,” the Doctor says, annunciating very clearly as he turns to her, “I should like to drink it.”

“It is very tasty; you’re right,” she replies, devilish gleam in her eyes, as she raises the bottle to her lips again. It is nearly empty.

With a squawk of outrage, the Doctor darts at her; he doesn’t reach for the eggnog but for her arms, pressing her back against the railing and kissing her thoroughly enough that Jack is a bit envious. She hitches a leg around his, and his hands are on her arse, pulling her close; are all over her, in fact, and River is moaning deliciously, arching into him.

“Why don’t we -” Jack starts to suggest, but then he hears a metallic _snik-click;_ the Doctor steps back holding the eggnog and River fails to follow. Her eyes widen as she comes up against the limit of the handcuffs attaching her by both wrists to the railing.

“Sweetie -” she begins, dangerously.

“You were teasing me,” the Doctor says querulously, “and you were being mean. Now.” He settles himself in the nearer jumpseat with the remnants of his prize, and looks at Jack. “I want to see what you two get up to when I’m not around.”

Jack looks at River, who is glaring at the Doctor. “Erm. River doesn’t wear the handcuffs,” he points out, for the sake of accuracy.

“She does now.” It looks like River is going to have to argue her way out of this one herself, if she wants to. “Go on.”

“Not if she doesn’t want me to.”

Pinning her with a glare every bit as fierce as the one she is directing back at him, the Doctor orders, “Tell him, River.”

“Perils of a light-fingered husband,” she agrees, without looking away. “But you will pay for this.”

“I’m impaired,” the Doctor replies, with an attempt at wounded dignity that is completely spoiled by the crossed arms and distinct pout. “Her safe word is angel, Jack. _Go on_.”

Still not certain where this power struggle has settled, Jack waits for a sign from River. She stares at the Doctor for a moment more; then her lips twitch, and she glances at Jack. “He's sulking,” she observes, sotto voce, lips curving up. “He cuffed me to the railing and now he's sulking. Isn't he adorable?”

“I can _hear you_. And I am never adorable.”

Jack grins. “Yes, you are.”

Shaking her head, River temporarily dismisses her husband. “Come here, Jack. We might as well make the best of it.”

“Well. If it's the best you're after, it's a good thing I'm here,” Jack says, obeying with alacrity. Sliding a hand to the small of her back, just under her wide belt, he smiles down at her, strokes her lip with his thumb. She touches it with the tip of her tongue and winks.

“Make him jealous,” she whispers.

“Oh, I intend to.” Her hair doesn't get windswept, just messier; it sparkles with tiny drops of melted snow and Jack buries his hand in it, loving the feel of the strands slipping through his fingers. He tugs gently to raise her face, lets his eyes fall closed as he traces her lips with his tongue. Whatever she’s wearing is sweet and sharp and tickles his nose, mercifully nothing at all like eggnog; the things he does for that man -! Never one for passivity, River meets his tongue with her own, bites down on his lip; Jack wonders suddenly if they bite each other, or if it’s just him, if there is something about him that makes them both need to claim him or whether it’s just that they know he likes it.

The handcuffs clink as River tries to move her hands and she growls. Sliding his right hand over the firm curve of her arse, Jack pulls her leg up, letting his fingers trail across her inner thigh. Distracted, she gasps and holds onto the railing and Jack groans as the heat of her presses against his cock. He tries to shift her leg so the heel of her boot isn’t stabbing into the back of his knee. “You could maim someone with these, love.”

River grins, and pulls him tight against her again. “Yes,” she purrs, “I could,” and how she can make a threat of bodily harm so sexy he could almost beg for it he he doesn’t know, especially when _she’s_ the one in handcuffs -!

“No maiming,” the Doctor says, and River pouts.

“You can be so tiresome,” she complains, but trails off as Jack gently tilts her head back further, kisses down her throat and licks at her collarbone. “Jack,” she sighs, “never minds,” and he hitches her leg up a little higher, running his fingers teasingly up and down her thigh.

Rocking his hips slowly against her, Jack whispers, “The boots will have to go.” He lets go her hair, moves his hand to undo her belt as he kisses back up her neck and licks her ear. She shivers, and licks his in turn.

“I like the boots.”

“You should have planned better, then.” Belt gone, he can run his hand under her long jumper, up the soft skin of her belly to cup a satin-covered breast. He rubs a thumb over her nipple and she arches into him. “Trousers won’t do at all for what I have in mind.” There is a muffled noise from the Doctor, and Jack looks over to see him slouched in his seat watching them voraciously, stroking himself slowly through his trousers; the empty bottle of eggnog lies discarded on the floor. Suddenly impatient, Jack catches his eye and jerks his head. “Come here.”

His claims of impairment seem exaggerated as he stalks over to them with fluid grace. Jack lets River's leg down and pushes her jumper out of the way to reach around and unfasten what feels like a delightful bit of satin and lace; it's a bit limiting, this being chained to the railing, but Jack is nothing if not accommodating.

“I knew you wouldn't be able to sit it out.” She sounds satisfied but it's not the kind of satisfaction Jack wants to hear. Pushing the bra up, he slides both hands over her breasts, brushing across her pebbled nipples, thumbs tracing the curve of sensitive skin underneath. Instead of kissing her as Jack was expecting, the Doctor works a hand into her hair and nuzzles her cheek as she moans.

“Lie to me all you like, River,” he murmurs, voice dark and intent; Jack's knees go a bit weak and he isn't even the target. “You can't fool me. I can smell how much you like this.” Then the Doctor's other hand is drifting across his arse, dipping briefly between his legs; Jack upgrades himself to secondary target and hums appreciatively.

“I like Jack,” she claims breathlessly. “Don't flatter yourself.”

Jack grins and wedges a thigh between her legs as the Doctor growls and bites her ear; there's that question answered anyway. “You like being tied up.”

“I -” Whatever argument she was going to make turns into a loud moan as Jack pinches her nipples; she grinds against his leg, holding tightly to the railing. Why she even _wants_ to win this argument, he can't imagine.

“Boots, Jack,” the Doctor reminds him.

He drops his hands reluctantly, with one last tweak that results in a muffled exclamation. “Yes sir,” he says; the Doctor rolls his eyes and swats Jack's arse, and Jack grins. It's rare he can get away with that. River's boots, shiny and red and practically a work of art with her calves to fill them out, are, somewhat to Jack's disappointment, done up with zippers and not laces; it is quicker, though. She picks up her feet absentmindedly when he prompts her to, distracted by the Doctor's tongue in her mouth. He pulls off his own boots as well, the better to kneel comfortably, adjusts himself, and runs his hands up River’s legs. Her knees wobble as he strokes the ticklish spot behind them; she moans and the handcuffs clink again, and the Doctor laughs. His hand is up her jumper, incidentally holding it out of Jack’s way. “More where that came from,” Jack promises, and places kisses in a line up her thigh as he opens her trousers and works them down, along with her knickers. When his lips reach bare skin she shivers.

“Get _on_ with it,” she gasps, trying to wriggle the rest of the way out of her trousers. She is well caught though, between Jack and the Doctor and the railing, and can’t do much more than groan in frustration as Jack laughs and licks at the crease of her thigh. The Doctor nudges his knee and Jack, willfully misinterpreting, leans over to nuzzle the front of his trousers.

“Jack!” he cries, startled back to his normal voice. “No, I -” Mouthing gently at his cock, Jack exhales a breath he knows feels like a furnace blast to the Doctor at first, especially after the cold outside. The Doctor moans, hips thrusting helplessly, head falling to rest against River’s.

River laughs breathlessly as Jack slides his hand between her thighs, just brushing against brown curls. “This is why you’re meant to tie _him_ up. He had us both convinced he was taking orders, and now -” Smirking, Jack turns her complaint into a whimper by the simple expedient of moving his hand up slightly.

“Naughty girl, River,” he says, voice a low croon as he rubs slowly back and forth, fingers sliding slickly, pressing a little more against her clit each time. “Look how wet you are.” Pulling his hand away, he licks his fingers, watching her watching him with wide, dark eyes. The Doctor is staring mesmerised as well, feeling every movement of Jack’s head against his cock, and there is nothing in all the universe Jack has found yet that compares to the rush he gets when these two are both focused on him. He takes a deep breath, and does _not_ press his free hand to his cock; not ready, just yet, to give up the upper hand. “You _love_ being tied up. Lying to us, all this time.”

“Jack bloody Harkness, you are an incorrigible liar and a shameless tease and if you don’t get back here this _instant_ -”

“You’ll maim me?” Jack suggests, laughing up at her.

“Can’t you two communicate without threats?” the Doctor laments. He crouches down, considering Jack mock-sternly, and raises a hand to his face. Firmly, deliberately, he traces a line from the centre of Jack's lips to his chin with his thumb, continues on down his throat. As a frisson of nervous arousal flows through him, Jack swallows, suddenly sure his most recent lie was when he told himself he had the upper hand. The Doctor leans in, lips cool against Jack's, tongue touching his just briefly. “Make her scream, Captain,” he whispers, and Jack completely fails to hold back his shocked howl as the Doctor squeezes his cock. “And then it will be your turn.” He stands, looking very satisfied with himself, as Jack rests his head against River's thigh, catches his breath; she squirms helpfully as he pulls her trousers off. “I've generally found positive reinforcement works much better.” His hand comes to rest on Jack’s head, carding slowly through his hair, and he muffles River's moans with a deep kiss.

Bemused at having lost so easily to someone who gets drunk on eggnog and lies even when he’s trying not to, Jack picks up River's right leg, licks the back of her knee just to feel her jump, and sets it over his shoulder. She tugs him forward impatiently, but he doesn't go just yet. Stroking her clit lightly, he watches her shudder, hips twitching toward him, hands clenched on the railing. “You're beautiful,” he says quietly. “He doesn't tell you often enough, River, you're a star we want nothing more than to orbit. We're just very bad at doing what we want.” She groans and pulls away from the Doctor, looking down at Jack with wild eyes, swollen lips. “I could do this for hours.”

“I know,” she gasps. “ _Don't_.”

Grinning, Jack gives in to the pull of her leg, the push of the Doctor's hand, and leans forward to suck sharply on her clit. Her cry turns to a desperate sob when he slides two fingers into her, and she presses against him, wet and wanton. The Doctor moans quietly, fingers tight in Jack’s hair, and he wonders - if the Doctor could smell her arousal before, what must it be like now? Any reaction on his part to human pheromones must be learned, but it is certainly well reinforced by now. Tongue moving in small circles, Jack bends his fingers, pressing upward firmly as he fucks her, no longer teasing. Her leg is tense around his shoulder; he slides his other hand up to her hip to hold her steady, provide some support for a knee looking decidedly wobbly.

“More, please, more -” Jack hums in acknowledgement and she moans; he hums again, amused, and she grinds against him. “ _More_.” Instead he slows down slightly, tongue lapping gently at her, fingers keeping a steady rhythm. “Jack!” she sobs in frustration; hearing his name said in new ways is one of the little joys of life that keep him going, and he hums happily again. This pace, he knows from experience, will carry her right to the edge of orgasm and not over it, which, well, it probably was very frustrating for her last time, admittedly; has she done that yet? It doesn’t really matter; he isn’t planning to draw it out today, but he does love listening to her, threats and all. The Doctor clearly does as well, because whatever he’s doing it doesn’t seem to involve her mouth.

She stops fighting him after another minute, relaxing around his fingers, her leg not pulling at him quite so insistently. He firms his tongue, drawing noughts and crosses until she’s whining in need above him, hips rocking ineffectively. Then he finally speeds up his hand, sucks hard on her clit, and she screams, high and breathy and gloriously unrestrained. When she cries out again and starts to relax, panting, Jack stills his hand, and licks gently at her whilst she comes down.

The Doctor tugs at his hair and Jack looks up. “Come here, Jack,” he says, smiling, arm about River’s waist to hold her up. Carefully settling her foot on the floor, Jack stands; the Doctor grabs his wrist and Jack realises he was about to absently wipe his hand on his trousers. “No,” he says, and pulls Jack’s hand to his mouth, licks palm to fingertips, staring at him the while with those deep, timeless eyes. Jack shudders, and goes a bit lightheaded with the sudden flow of blood to his groin. The Doctor licks him again, a hint of smug smile around his eyes, then sucks Jack’s fingers into his mouth, tongue sliding slowly against them.

“You,” Jack says cleverly. “I, you -”

There is a _click_ , and then a hand sliding down his spine, and River, voice roughened and sultry, says, “You’ve been a _very_ good boy, Jack.” She leans in to kiss him but he can’t tear his eyes from the Doctor, so she settles for biting his neck and he moans. “Aside from some teasing which may require repayment. It’s your turn.”

-+-+-+-

 


End file.
